Vapor separators are typically used to separate fuel vapor from liquid fuel injected into a marine outboard motor. A conventional vapor separator is usually connected with inlet and outlet fuel lines between a fuel tank and a fuel-injected engine of the outboard motor. The vapor separator typically includes a water separating filter carried in an enclosed reservoir in which a quantity of liquid fuel is maintained with a float valve. A fuel pump receives liquid fuel from the reservoir and pressurizes it for downstream delivery through fittings and hoses to a fuel rail in fluid communication with the fuel injectors. A fuel pressure regulator is typically carried by a downstream end of the fuel rail and returns excess fuel not injected into the engine from the fuel rail to the vapor separator through fittings and hoses.
The returned fuel is often heated, having been routed near the engine through the fuel rail, and having also been heated by the fuel pump prior to delivery to the fuel rail. Accordingly, fuel vapor is generated when the heated return fuel enters the reservoir. The vapor separator typically includes a vent valve to vent the fuel vapor in the reservoir outside of the vapor separator to the engine for combustion therein.
Conventional vapor separators may include one or more of the following drawbacks. First, excessive space may be required to package a conventional vapor separator and its inlet and outlet hoses under cowling of an outboard motor. Second, a conventional vapor separator may leak when tilted past horizontal. Third, the fuel pump may generate fuel vapor, which may be delivered downstream to the engine. Fourth, return fuel may be heated, thereby contributing to fuel vaporization. Fifth, fuel pump motor wires may define a leak path for fuel or the fuel pump may extend out of the reservoir.